Little Shop of Horrors (1986)

Nature has been found to inspire some of the most iconic monsters of our time; wolves begat wolfmen, vampire bats make Count Dracula's image more alarming and threatening, and tadpoles with see-through intestines inspired Satoshi Tajiri to make Poliwag. The film "Little Shop of Horrors" derives its monster's inspiration from Venus Fly-traps, having a more literal bent on plants with Venus in their name. 
The movie is based off a Broadway musical so the film is interspersed with songs which really help along the narrative of the story, although the "Greek Chorus Supremes" can be a bit distracting.  Rick Moranis and his co-star with a speech impediment/fake accent can sing surprisingly well.  One of the most enjoyable of these songs is Steve Martin's take on why people fear dentists; energetic, a bit creepy, but plenty of fun because Steve Martin's a loon. The real star of the show though is the puppetry skills that make Audrey II, the man-eating plant, really come alive.  In a sad sense of loss, you'd realize such simple yet elegant special effects are lost on a younger generation fed CGI images from any studio with the cash and a half-baked story.  But this plant is seriously a wondrous monster that not only menaces but entertains, singing some pretty amazing songs and having jaws that would make the famous shark jealous.
Overall, fun, crazy, and quite musical bit of film with a memorable monster that stands up amongst the greats, erm ingrains in the soil amongst the greats.

But voiced by a black guy.